再生骨料特征参数对混凝土强度的影响

摘要/Abstract

摘要： 再生骨料(RCA)对混凝土的性能影响极大,了解RCA对混凝土性能的影响,对提高RCA的利用效率,降低建筑行业碳排放并响应国家“双碳”政策至关重要。本文借助CT扫描技术获取了四组不同RCA替代率下掺锂渣再生混凝土的骨料特征图像,运用数字图像处理方法获得了RCA的形状系数(SF)、棱角度(AN)、棱角与表面纹理(AT)指数及三维球体度(SP),分析了它们的分布规律及特点,并通过灰色关联分析方法建立了骨料特征参数与抗压强度的联系。结果表明:RCA具有较高的不规则性,由于骨料残留的砂浆量不同,其表面呈现粗糙且多棱角的特点;四个骨料特征参数均表现出较高的灰色关联度,其中SP关联性最大,达到0.942;在合理的骨料混合比例下,试验样品可以满足C30混凝土强度的要求,且在30%(质量分数)RCA替代率下力学性能最优。

关键词: 再生混凝土, 骨料特征参数, 灰色关联度, CT扫描, 抗压强度, 锂渣

Abstract: The performance of concrete is greatly affected by recycled coarse aggregate (RCA). Understanding how they affect performance of concrete is crucial to maximizing RCA utilization, reducing carbon emissions in the construction industry, and contributing to achieving national carbon peaking and carbon neutrality targets. Four groups images of aggregate characteristic of lithium slag recycled aggregate concrete with different RCA replacement rates were acquired by using CT scanning. The shape factor (SF), angularity (AN), angularity and surface texture (AT index), and three-dimensional sphericity (SP) were calculated by using digital image processing techniques. Based on the analysis of their distribution rules and characteristics, a gray correlation analysis method was used to determine the relationship between different aggregate characteristics parameters and compressive strength. The results show that the RCA has a higher irregularity, and its surface is rough and angular due to the different amounts of paste remaining in the aggregate. There is a high gray correlation degree among the four aggregate characteristic parameters, among them, the SP correlation degree reaches the maximum, 0.942. Samples meet the strength requirements of C30 concrete in aggregate mixing ratio appropriately and gain the best mechanical properties with RCA replacement of 30% (mass fraction).

Key words: recycled aggregate concrete, aggregate characteristic parameter, grey correlation degree, CT scanning, compressive strength, lithium slag

中图分类号:

TU528

秦拥军, 渠长伟, 罗玲, 田盼盼, 陈洁静. 再生骨料特征参数对混凝土强度的影响[J]. 硅酸盐通报, 2022, 41(10): 3615-3623.

QIN Yongjun, QU Changwei, LUO Ling, TIAN Panpan, CHEN Jiejing. Influence of Characteristic Parameter of Recycled Aggregate on Concrete Strength[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2022, 41(10): 3615-3623.

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